These don't need to be good or even useful. For example:
Headless Horse: A statue of a horse missing it's head. (Could optionally be a wondrous figurine that turns into a regular decapitated horse.)
Razor Apple: Don't tell your players, but this apple has a razor in it. If they eat it without checking it for traps, they take 1d6 bleed damage.
Ouija Board: Lets you cast Speak With Dead using it, but doing so causes you to be attacked by a ghost.
Masqueraid - a mask in the form of a humanoid race or creature. The item is a one use Hat of Disguise that makes the wearer appear to be a stereotypically costumed member of the race/type depicted on the mask. The effect lasts for two hours.
Ouija Board: Lets you cast Speak With Dead using it, but doing so causes you to be attacked by a ghost.
Actually, Occult Adventures has both mundane and magic spirit boards already. Lots of things in that book could be used for Halloween spookiness, actually.
mimic trick or treating back pack functions as a normal back pack except it eats all the food put into the back pack especially the candy
How does something eat all the food, especially the candy?
Hallowed Pumpkin: Causes you to be attacked by undead at night unless you fill it with candy. If you try to get rid of it, it just comes back until you cast remove curse.
Dirty Trick or Treat: you wear this costume and demand that someone (typically an opponent) give you candy. If they don't, you get a free, non-provoking Dirty Trick maneuver on them.